Swallowing the first pill (or giving the first injection) of your new type 2 diabetes medication comes with some uncertainties: Will it work? When will your blood glucose improve? Will you experience side effects?

A lot of these questions can be answered—to a degree.

Drug Dynamics

How fast a medication will work depends on several factors, says George Grunberger, MD, FACP, FACE, president of the American Association of Clinical Endocrinologists. Those factors include:

the drug’s absorption into the body

distribution of the drug within the body

how the body metabolizes the drug

How the drug works in the body can help you determine how fast it will take effect. Each oral medication has a different mode of action, and the mode of action can influence how fast a person will respond. “And, of course, every patient is different,” says Grunberger.

Not only will people respond differently to the same drug, but some people may have no response. “Probably 15 percent of people [in clinical drug trials] never respond,” he says.

Understanding the terms used to describe the actions taking place in the body is important to parsing out how and when certain medications will work, says Sam Ellis, PharmD, BCPS, CDE, associate professor in the Department of Clinical Pharmacy at the University of Colorado. (For more on that, “Terms to Know,” p. 57.)

Minimum vs. Maximum

In the first few days after you start a new medication, you may start to see lower blood glucose readings. That dip happens before the drug hits its maximum blood glucose–lowering potential. That, Grunberger says, comes in time.

This has to do with the medication reaching what’s called its “steady state”—when the amount of drug entering the body equals the amount leaving it. When the drug reaches this point in the bloodstream, you’ll start to see the greatest blood glucose drop, but the size of the effect depends on how each medication works in the body and how each person metabolizes drugs.

One factor that comes into play is the amount of time it takes the body to get rid of half of the dose of a medication, known as a drug’s half-life. Once they know that, researchers can predict how fast a drug will reach steady state in the body. Of course, plenty of factors can influence when a drug reaches this state in an individual, such as kidney function, age, obesity, genes, and how quickly a person metabolizes drugs. If you have kidney disease, for instance, medications may spend more time in your system before exiting. Because of this, it may take longer for the drug to reach its steady state—and its greatest blood glucose–lowering effect. And that effect may be greater due to the accumulation of the drug in the body.

Evan Sisson, PharmD, MHA, CDE, associate professor in the Department of Pharmacotherapy and Outcomes Science at Virginia Commonwealth University, says that even with all of those factors to consider, you can follow a general rule of thumb: Expect to see 90 percent of the effects of most type 2 oral medications by the end of two weeks, with the exception of thiazolidinediones (Actos and Avandia), which take much longer.

Class and Time

In Combination

If your blood glucose is uncontrolled with one medication, your doctor may decide you need multiple drugs to hit your target. If you are adding a medication to your diabetes management regimen, each medication will follow its normal course of onset, says Ellis. Giving these types of drugs together doesn’t really affect how the body processes them. But when you change a dose or switch drugs completely, you might notice blood glucose elevations until the new drugs take effect. “Don’t give up on things too quickly,” he says.

Testing, Testing

So, how do you know if your medication is working? Check your blood glucose more often, at least for a little while. Stay informed by testing first thing in the morning and then before or after meals—or both, depending on what your doctor advises.

Once you are at a stable dose (about two weeks for most medications), you may be able to check less often. If you’re starting on a sulfonylurea or insulin, you’ll also want to watch for hypoglycemia. “You have to do more finger-sticking just to make sure you don’t get too low,” says Grunberger.

Follow-up Time

The timing of your follow–up appointment with your diabetes care provider will depend on a number of factors, including how long it takes for your medications to reach maximum effect, expected side effects, and other health conditions you may have.

If you are having concerns or noticing what you think may be side effects early on, contact the prescribing care provider as soon as possible. You can also consult a member of your diabetes care team. “You have a pharmacist who can think about the drugs, a nurse practitioner [who] can help with the management of other issues, as well as a dietitian and a diabetes educator,” Sisson says.

Key to Success

“No medication works unless you take it,” says Grunberger. It’s up to the doctor to make sure you know exactly how and when to take your medications. “No patient ever leaves my office without written instructions of what we’ve actually decided to do,” says Grunberger. But that’s only half of it. It’s your job to actually take the meds.

The treatment regimen should be a collaboration between you, your heath care team, and often a caregiver or family member. And it should be based on what is reasonable for each person. “Sometimes providers forget that and prescribe a regimen that is so difficult that somebody just can’t reasonably do it,” Sisson says. “It’s up to the provider to say, ‘What’s reasonable for you?’ ”

Mutual trust is important so you and your provider can arrive at agreed-upon treatment goals. But you also have to understand that though these medications manage diabetes, they’re not a cure. “You can’t just take a couple doses and expect it to go away,” says Sisson.

They’re also not a substitute for lifestyle changes, says Grunberger. You have to use medications along with healthy eating and exercise for the drugs to work.

“We know, based on clinical studies, what kind of efficacy we should be seeing with these drugs,” says Ellis. Not seeing good results? It may be time to examine your treatment regimen and identify if taking the medication as prescribed is a problem for you.

Along with nutrition and physical activity, medication is one of the most important aspects of diabetes management. If you are having trouble sticking to your plan, that’s OK. Talk to your doctor or diabetes team about why you’re having issues, and work together to fix it. And don’t get defeated: Grunberger says the most important aspect of taking medication is not giving up too soon. “Make sure that you really, really give every medication a chance to work,” he says.

Terms to Know

Dynamics: The therapeutic effects and side effects of the drug

Half-life: The amount of time it takes the body to excrete half of the drug dose. Knowing this can determine when the steady state drug concentration will be reached.

Mechanism of action: How the drug works in the body

Pharmacokinetics: The study of the time it takes for a drug to be absorbed, distributed, metabolized, and excreted by the body

Steady state: The point at which the amount of drug coming into the body is equal to the amount of drug excreted from the body. The maximum effect of the drug will be evident after the blood concentrations reach this state.